I have been looking at the data from various astronomical sources and trying to define the overall patterns and there is definitely a basis for an event that is 10-20 billion years ago. I say that imprecisely because it need not be precise any more than saying the half moon has about a 45° angle when at 45° latitude. It would seem that there is no reason to believe that a massive "black" hole or very-very large dark star (1024 solar masses) reached a critical mass and popped. In larger universe this would be a speck in the overall frame work and it would seem that much of what happens is cyclic. It would be reasonable to assume that a massive shock wave of dark matter was just beyond the reach of our instruments and technology. It might account for some variations in expansion. Just a random thought of the day however. There are many patterns there in the stars and I sometimes wonder if others were able to see those patterns long ago. It requires the eye of the beholder be attuned to the possibilities. The debris could shield the rest of the infinite universe from us and when instruments can be made to peer through that, perhaps the theories will change. I am always just guessing, as I rarely visit the edge of the known universe anymore as I am too busy blogging.